Northern Thailand is dying for a smog solution

Bangkok: Chiang Mai air is generally clean, but this year’s annual smog from mid-February to mid-April has been so bad there have been days when it has had the most poisonous city air in the world. Due to the continued absence of effective government intervention to tackle the smog a loose group of academics, doctors and students, many from Chiang Mai University (CMU), has been trying to address the problem for the last few years.

Burning in the northern Thai countryside and beyond creates the
smog. Dr Poon Thiengburanathum from CMU’s School of Public Policy has been
tracking the burning since 2012. He said approximately 60% to 70% of it
happens in forested areas while 30% to 40% is in agricultural areas – but
over the past seven years, burning has decreased in Thailand but increased in
neighboring Shan State in Myanmar, and Laos.

Dr Poon explained that previously most farmers in the mountains
were subsistence farmers so they did relatively little burning, but about 15
years ago they started to farm commercially and increased the amount they grew
and burned. This coincided with an increase in demand for corn to feed cattle
by large industrial food producers such as CP Foods who guaranteed to buy all
the corn farmers could produce, so many started growing it.

Unfortunately, the easiest and cheapest way of disposing of the
corn waste left after harvest is to burn it. Due to public pressure, there has
been a reduction in the number of new corn farms being set up in northern
Thailand, though Dr Poon said there is a possibility that corn production has
just shifted into Shan State, which could account for increased burning there.

The smog problem is exacerbated because Chiang Mai lies in a bowl surrounded by mountains and at this time of year there is little wind and a climate inversion that traps smog near the ground under a layer of warmer air.